What Is This Worm Looking Thing In My Tank?

[bentz69]

I have a 2.5 gallon tank with one betta and bunch of red cherry shrimp. Ive had the betta only for a few months with no problems. I added several shrimp a few a weeks ago and again, the tank was fine. I ordered 5 marimo moss balls from ebay and recieved them a few days. I cleaned them the best I could and added them to my tank.

Today I see what looks like a little worm about 1/4 - 1/2 inch long on the glass. I only found one so far.

What is this thing and is it a threat to my tank?





https://youtu.be/UZaMPDB8MvY

 

[Baccus]

It looks like a detritus worm, usually pretty harmless to anything in a tank since they are just tank cleaners. Their proper name is Annelid family most likely in the Oligochaete group.
If my suspicion is correct it (they) probably came with the moss balls and you only need worry if you see masses of them appearing on the glass because that means their usual habitat in the substrate has gone bad. Too many of these worms all dying at once can cause ammonia spikes and through the ecology of the tank out of whack.